The present invention relates to a new and improved construction of base fuze or base percussion fuze for spinning projectiles, which is of the type comprising a firing or ignition pin for piercing a detonator cap, a hammer sleeve secured to the firing pin, and a self-destruction spring under the action of which the hammer sleeve together with the firing pin can be displaced towards or against the detonator cap.
There is already known to the art an impact fuze of this general type wherein a relatively large hammer sleeve is displaceably arranged within a cylindrical bore. The hammer sleeve is provided at its front end with a firing or ignition pin which must be pushed or displaced with a certain speed against a detonator cap to insure reliable response of the latter.
The state-of-the-art impact fuze requires a relatively large self-destruction spring which is capable of accelerating the mass of the hammer sleeve to such a degree that the detonator cap is pierced at the required speed. In the event that the projectile impacts against the target at a small angle of, for instance, less than 5.degree. and is subsequently deflected, then inertia forces directed perpendicular to the fuze axis act upon the hammer sleeve and the self-destruction spring. The hammer sleeve and the self-destruction spring are biased against their guide and the thus resulting frictional forces prevent displacement of the hammer sleeve. The firing pin then impacts with too small velocity or speed against the detonator cap, with the result that there is no longer positively insured for detonation or firing of the detonator cap.
In order to avoid this difficulty the mass of the hammer sleeve must be as large as possible upon impact, in order to be able to overcome the frictional forces, whereas, on the other hand, during self-destruction the mass of the hammer sleeve should be small to insure that the self-destruction spring need not accelerate any large mass.